Methods and apparatus for providing DC power for low voltage lighting

ABSTRACT

A DC power supply for lighting includes low voltage driver electronics for any suitable load such as lighting along with a supervisory controller that communicates to the driver electronics via any suitable digital communication protocol. Each driver&#39;s output ports include a 3rd wire that communicates to the low voltage load fixture for the purpose of auto-negotiating the appropriate power level without first having to energize the fixture.

This application claims priority to U.S. Provisional Patent Application62/241,621 filed Oct. 14, 2015.

FIELD OF THE INVENTIONS

The inventions described below relate to the field of low voltagelighting.

BACKGROUND OF THE INVENTIONS

Current negotiated power standards lack a requirement for a standbypower level to be available such that the load device can turn on activeelectronics and respond via a full communication stack.

SUMMARY

The devices and methods described below provide for a DC power supplyfor loads such as lighting. The DC power supply includes low voltagelighting driver electronics along with a supervisory controller thatcommunicates to the driver electronics via any suitable digitalcommunication protocol. The output of each low voltage lighting portincludes a third wire that communicates to the low voltage lightingfixture for the purpose of auto-negotiating the appropriate power levelwithout first having to energize the fixture.

The DC power supply housing includes light emitting diode (LED) driverelectronics along with a supervisory controller that communicates thedriver electronics via digital method such as the digital addressablelighting interface (DALI). LED constant current or constant voltagestyle signals are then originated to LED fixture assemblies that containno drivers of their own; only LED arrays manufactured by others usingany suitable means.

Through the use either of a backplane circuit board or wiring harnesseseach driver's output ports include a 3rd wire that communicates to theLED fixture for the purpose of auto-negotiating the appropriate powerlevel without first having to energize the fixture. This allows fixturebrands and types to be mixed and even moved from port to port withoutthe risk of damage to the fixture or requiring expertise by theinstaller to understand how to balance (i.e. bias) LED array powerlevels for optimal output.

Optionally, driver manufacturer's would be allowed to license themethodology such that their driver could perform the auto-negotiation onits own. Second, the housing could optionally implement a method whereLED drivers' form factors are modified by the manufacturer to includeadditional input pins either in the form of discrete connectors orcard-edge connector format such that inclusion in a particular slot setsthe bus address for communicating to the master controller in thehousing. An example being if the LED drivers in each slot were DALIslaves, slot 1 would take bus address 1, slot 2 bus address 2, etc. suchthat the master controller could address each slot individually withoutrequiring a technician to intervene by supplying individual busaddresses as is required to individually address DALI drivers orballasts mounted directly in fixtures. An additional benefit is now thateach slot could be purpose chosen based on price, performance, brand, orother factors even allowing the installing contractor, facilitymaintenance professional, or specifier to call out differentcapabilities for each output channel without impacting their choice infixture form factor, aesthetics, CRI, or other similar factors. The LEDfixtures, in effect, become as interchangeable as incandescent lamps.

The devices and methods described below:

-   -   1. Remove cost from LED fixtures;    -   2. Remove UL certification cycle from LED fixtures;    -   3. Removes LED driver control performance specification from        fixture manufacturer;    -   4. Prevents damage to LED fixtures when swapping out driver        technologies;    -   5. Allows mix and match or field comparison of driver        performance with a given fixture;    -   6. Reduces LED drivers to a single standard form factor;    -   7. Reduces the number of global controller addresses and/or        radios for per-fixture control schemes from 1:fixture to        1:housing-diveristy (likely models are 4 slot, 8 slot, 16 slot,        32 slot) thus reducing commissioning and re-commissioning times;    -   8. Reduces UL certification “pairing” cycles for drivers from        1:fixture (potentially 10,000's) to 1:housing-diveristy (likely        models are 4 slot, 8 slot, 16 slot, 32 slot);    -   9. Added efficiency through the ability to bulk-power a housing        through a single large AC/DC conversion or DC/DC conversion;    -   10. Added safety through allowing DC class 2 wiring to fixtures;    -   11. Added safety through having LED driver assemblies of        whatever form factor in a cavity/barrier scheme that isolates        high voltage connections from service personnel more effectively        than a fixture housing;    -   12. Long term serviceability improvement by allowing potentially        EOL or expensive drivers to be easily field replaced without        fear of damaging the fixture.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of a low voltage lighting power housing.

FIG. 2 is an illustration of the details of the wired terminalconnections of the low voltage lighting power housing of FIG. 1.

FIG. 3 is a block diagram of an alternate low voltage lighting powerhousing.

DETAILED DESCRIPTION OF THE INVENTIONS

DC power supply 10 illustrated in FIG. 1 includes one or more LEDdrivers, such as DC or LED drivers 11, 12, 13 and 14 along with asupervisory controller 15 that communicates with the LED drivers via anysuitable method such as digital communications, for example using DALI.Supervisory controller 15 is capable of receiving wired or wirelesscommunication from wired load controllers 16 and wireless loadcontrollers 18 communicating control accessories such as motiondetectors, switch stations, ambient light sensors, occupancy sensors andother load controllers. For example wireless load controller 20exchanges wireless communication signals 21 via antenna 22. Similarly,wired load controllers 16 exchange control signals 24 with supervisorycontroller 15.

Any suitable line voltage energy 30 is shared within power supply 10 toprovide energy for supervisory controller 15 and LED drivers 11-14. TheLED drivers are optimized power supply units for any suitable load suchas lighting loads 32 and 34 and they provide drive signals or energy 35using either constant voltage pulse width modulation or constant currenttopology. LED constant current or constant voltage style signals 35 arethen distributed to the loads such as LED fixture assemblies thatcontain no drivers of their own. Suitable lighting loads can be simpleLED arrays manufactured by others using any suitable means.

Loads 32 and 33 may be any suitable DC load such as an array of LEDs.Loads 32 and 33 are connected to output connectors of power supply 10using cables with at least three conductors such as cables 32X and 33Xrespectively. By using power supply 10 with its included LED drivers,loads 32 and 33 do not require integrated LED drivers and are understoodto be driverless loads.

DC power supply 10 includes power output connectors 36 having at leastthree conductors, pins, sockets or terminals such as terminals 36A, 36Band 36C. Terminals 36A and 36B conduct the hot or power signal and thecommon or ground signal for powering the load such as the LED array.Terminal 36C is the connection between supervisory controller 15 and theloads via wiring harness 37 through the LED drivers to communicate withthe load or, more specifically, in some cases with a communications chipsuch as an EEPROM 38 incorporated into the load as illustrated in FIGS.1 and 2. Driverless loads such as loads 32 and 33 of FIG. 1 or loads 39and 40 of FIG. 2 incorporate a third terminal such as terminals 39C or40C respectively in their power connector for the purposes of receivingcommunication from the master or supervisory controller.

Any suitable electronic communicating integrated circuit capable ofcommunicating over a single wire may be incorporated in each load suchas chips 41 and 42. such as the Dallas 1-wire standard from Maximelectronics included at manufacture from the light source OEM andcontaining an alphanumeric string encoding the power requirements tosafely operate the LED light source for the purpose of allowing thecoordinating controller to query the power requirement of the connectedlight source at each 1) power cycle, 2) plug in, and 3) unplug/re-plugevent such that power delivery is always appropriate for the connectedLED light source to make the DC system self-biasing (e.g. balanced)without the need for a fixed prior configuration.

Through the use either of a backplane circuit board as illustrated inFIG. 3 or with a wiring harnesses such as wiring harness 37 illustratedin FIG. 1 or 2, the output port of each of LED drivers 11-14 includes a3rd wire that communicates to the LED fixture (load) and the supervisorycontroller 15 for the purpose of auto-negotiating the appropriate powerlevel without first having to energize the fixture. This allows fixturebrands and types to be mixed and even moved from port to port withoutthe risk of damage to the fixture from an improperly balanced driver orrequiring expertise by the installer to understand how to balance (i.e.bias) LED array power levels for optimal output.

The method of auto-negotiating shall be implemented using any suitabletechnique such as by transmitting a data set or packet such as a simpleencoded string from the LED array (load). For example, data packet 44includes the required voltage and current levels of load 33 tosupervisory controller 15 such that the supervisory controller candistribute the information to the drivers.

Optionally, driver manufacturer's would be allowed to license themethodology such that their driver could perform the auto-negotiation onits own.

A power supply such as power supply 10 illustrated in FIGS. 1 and 2 orpower supply 50 of FIG. 3 may also be used to charge one or morebatteries where the voltage and current needs can be known and includedon the 1Wire EEPROM for the charger output to read before engaging. Forexample, a 6V cell for exit sign needs 7.2V @ 400 mA to charge whereas a24V cell for light fixture needs 29V @ 500 mA to charge, but the samechannel could support both for charging purposes by first reading backthe charging input required. Other related charging system applicationsare include appliance devices such as cordless/cell phone, handheldpower tools, etc.

The devices and methods as described may also include wired low powercommercial ceiling accessory devices which could also auto-negotiate fortheir required accessory voltage safely by including the EEPROM and 3rdwire connector. Examples include HVAC devices such as VAV controllers,IO controllers, controllable shade motors, electro-chromic glasscontroller, or controllable skylight dampers.

The devices and methods as described may also include wired-for-powerbut wireless-for-communication devices of any kind where communicationvia an unsecured connection such as USB or via an expensive per porttech like PoE is not optimal with examples including wall mounted touchscreen controllers, thermostats, and digital RF communicating lightswitches.

The devices and methods as described may also include the power supplyas discussed above supporting a connector, wiring harness, or socketenabling the in-field addition of a programmed EEPROM with the powernegotiation parameters for a device type that did not include the chipfrom the factory or vendor that chose not to factory-include thecapability.

The low voltage lighting system uses power auto-negotiation technologycircuit such as Maxim-IC Dallas 1-wire or similar. The low voltagelighting driver housing uses standard commercial-off-the-shelf (COTS)LED drivers that are factory or in-field wired to the output ports andthe master controller.

An alternate power supply is illustrated in FIG. 3. Power supply 50incorporates backplane 51 and an industrial design method and formfactor such that insertion of a low voltage lighting driver such asdriver 52 into the backplane, or the socket of the backplane such assocket 51A, sets a communication bus address such that master controller53 can automatically address driver 52.

For example, if the LED drivers in slots 51A, 51B, 51C and 51D were DALIslaves, slot 51A would take bus address 1, slot 51 bus address 2, etc.such that master controller 53 could address each slot individuallywithout requiring a technician to intervene by supplying individual busaddresses as is required to individually address DALI drivers orballasts mounted directly in fixtures. An additional benefit is now thateach load and driver could be purpose chosen based on price,performance, brand, or other factors even allowing the installingcontractor, facility maintenance professional, or specifier to call outdifferent capabilities for each output channel without impacting theirchoice in fixture form factor, aesthetics, CRI, or other similarfactors.

Alternatively, the addresses of slots in the backplane such as slots51A, 51B, 51C and 51D may have their binary addressing set for each slotby means of pins pulled high or low via dip switches or other discretecomponents on the backplane, such as dip switches 54A, 54B, 54C and 54Dfor the purpose of automatically addressing the DALI communication toeach slot automatically so that LED drivers can be easily mixed,matched, and moved to different slots without affecting the ability ofthe master controller to address each slot individually.

Master or supervisory controllers such as controllers 15 and 53 have aglobal network connection, lighting control algorithm, DALI master, DALIslave, I2C/SPI, and UART/Serial connections for connection to LEDdrivers or a backplane.

While the preferred embodiments of the devices and methods have beendescribed in reference to the environment in which they were developed,they are merely illustrative of the principles of the inventions. Theelements of the various embodiments may be incorporated into each of theother species to obtain the benefits of those elements in combinationwith such other species, and the various beneficial features may beemployed in embodiments alone or in combination with each other. Otherembodiments and configurations may be devised without departing from thespirit of the inventions and the scope of the appended claims.

We claim:
 1. A system for providing DC power to a driverless loadcomprising: a power supply comprising: a supervisory controller operablyconnected to line power; a DC driver having an output with at leastthree conductors, the DC driver operably connected to line power and thesupervisory controller; a three conductor connector operably connectedto the output of the DC driver; and a cable operatively connecting thethree conductor connector to the driverless load to conduct energy andcommunication between the power supply to the driverless load; and anintegrated circuit for single wire communication embedded in thedriverless load.
 2. The system of claim 1 wherein the supervisorycontroller communicates with the DC driver using a digital addressablelighting interface protocol.
 3. The system of claim 1 wherein the DCdriver provides energy to the driverless load using constant voltagepulse width modulation topology.
 4. The system of claim 1 wherein the DCdriver provides energy to the driverless load using constant currenttopology.
 5. The system of claim 1 further comprising: one or more loadcontrollers operably connected to the supervisory controller forapplying or removing energy to the driverless load.